21015652291 has 2 divisors, whose sum is σ = 21015652292. Its totient is φ = 21015652290.

The previous prime is 21015652201. The next prime is 21015652321. The reversal of 21015652291 is 19225651012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21015652291 - 2⁹ = 21015651779 is a prime.

It is not a weakly prime, because it can be changed into another prime (21015652201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10507826145 + 10507826146.

It is an arithmetic number, because the mean of its divisors is an integer number (10507826146).

Almost surely, 2^21015652291 is an apocalyptic number.

21015652291 is a deficient number, since it is larger than the sum of its proper divisors (1).

21015652291 is an equidigital number, since it uses as much as digits as its factorization.

21015652291 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10800, while the sum is 34.

The spelling of 21015652291 in words is "twenty-one billion, fifteen million, six hundred fifty-two thousand, two hundred ninety-one".